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Sci Rep
. 2022 Apr 22;12(1):6636.
doi: 10.1038/s41598-022-10559-4.
Protein-bound sialic acid in saliva contributes directly to salivary anti-influenza virus activity
Kaori Kobayashi # 1 , Chika Shono # 1 , Takuya Mori 2 , Hidefumi Kitazawa 1 , Noriyasu Ota 1 , Yuki Kurebayashi 3 , Takashi Suzuki 3
Affiliations
- PMID: 35459785
- PMCID: PMC9033866
- DOI: 10.1038/s41598-022-10559-4
Abstract
The oral cavity is an entrance for respiratory viruses, such as influenza. Recently, saliva has been shown to exert both antimicrobial and antiviral activities. Thus, saliva may be a biological factor that contributes to the prevention of influenza infection. However, the actual salivary anti-influenza A virus (IAV) activity in individuals and its determinant factors are unknown. By assessing individual variations in salivary anti-IAV activity in 92 people using an established new high-throughput system in this study, we found that the anti-IAV activity varied widely between individuals and showed a significant positive correlation with protein-bound sialic acid (BSA) level (ρ = 0.473; p < 0.001). Furthermore, the anti-IAV activity of saliva with enzymatically reduced BSA content was significantly lower. These results indicate that BSA is a direct regulator of salivary anti-IAV activity and is a determinant of individual differences. Additionally, after comparing the anti-IAV activity across the groups by age, anti-IAV activity in young people (aged 5-19 years) were lower than in adults aged 20-59 years and elderly people aged 60-79 years. Our study suggests that BSA levels in saliva may be important in preventing influenza infection.